CircuitsGallery had posted many electronic circuit design projects suitable for School students as well as engineering students. Here we would like to demonstrate one of the hobby electronics projects called the visitor counter project. It will be a simple electronics project for school students.
A digital visitor counter is necessary to count how many people entered a party or a conference hall. The automatic visitor counter is a simple electronics hobby circuit and it can be applied to science fair projects for school students.
It can simply be done by this circuit, a light source and a light sensor are used to detect the person and display the count using seven segment display with the help of 4026. The light source and the light sensor are placed in such a way that the visitor will cross the light path when he enters the hall.
Automatic Digital Visitor Counter Circuit Diagram
Components Required for Automatic Visitor Counter Project
- IC 4026
- Transistor (BC548)
- Resistor (10K, 100)
- POT (100K)
- 7 segment Display (Common anode)
- Torchlight or laser
Visitor Counter Circuit Working Principle
- The light beam from the torch is continually hit on the LDR so the resistance of LDR is low and the voltage drop across LDR and ground is less than 0.6V
- The threshold voltage of 0.6V can be set by varying the POT 10K
- When a person or an object is passed between the light beams light will not hit on the LDR so the resistance of the LDR becomes high
- We have V=IxR (Voltage = Current X Resistance) i.e., the resistance of LDR is the high voltage across LDR becomes high
- If the voltage across LDR exceeds 0.6V then the transistor will ON and start conducting
- When the transistor is ON, the potential at point A becomes LOW and when the transistor becomes OFF, the potential at a will be HIGH
- As soon as the person crosses the light beam a LOW and HIGH voltage transition occurs at point A.
- Which is fed to the Clock of 4026 IC, it will start counting with the clock and display on seven segment display
4026 will increment the count when each person enters the room
The automatic digital visitor counter circuit is very easy to implement and its circuit section is also so simple. But if you can replace the light and LDR arrangement with a better and more modern sensor, it might prove better.